[PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[Zhang Changzhong]

The skb allocated by stmmac_test_get_arp_skb() hasn't been released in
some error handling case, which will lead to a memory leak. Fix this up
by adding kfree_skb() to release skb.

Compile tested only.

Fixes: 5e3fb0a6e2b3 ("net: stmmac: selftests: Implement the ARP Offload test")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
index 49af7e7..687f43c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
@@ -1654,12 +1654,16 @@ static int stmmac_test_arpoffload(struct stmmac_priv *priv)
 	}
 
 	ret = stmmac_set_arp_offload(priv, priv->hw, true, ip_addr);
-	if (ret)
+	if (ret) {
+		kfree_skb(skb);
 		goto cleanup;
+	}
 
 	ret = dev_set_promiscuity(priv->dev, 1);
-	if (ret)
+	if (ret) {
+		kfree_skb(skb);
 		goto cleanup;
+	}
 
 	ret = dev_direct_xmit(skb, 0);
 	if (ret)
-- 
2.9.5

Re: [PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[Leon Romanovsky]

On Wed, Dec 07, 2022 at 04:31:59PM +0800, Zhang Changzhong wrote:
> The skb allocated by stmmac_test_get_arp_skb() hasn't been released in
> some error handling case, which will lead to a memory leak. Fix this up
> by adding kfree_skb() to release skb.
> 
> Compile tested only.
> 
> Fixes: 5e3fb0a6e2b3 ("net: stmmac: selftests: Implement the ARP Offload test")
> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
> index 49af7e7..687f43c 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
> @@ -1654,12 +1654,16 @@ static int stmmac_test_arpoffload(struct stmmac_priv *priv)
>  	}
>  
>  	ret = stmmac_set_arp_offload(priv, priv->hw, true, ip_addr);
> -	if (ret)
> +	if (ret) {
> +		kfree_skb(skb);
>  		goto cleanup;
> +	}
>  
>  	ret = dev_set_promiscuity(priv->dev, 1);
> -	if (ret)
> +	if (ret) {
> +		kfree_skb(skb);
>  		goto cleanup;
> +	}
>  
>  	ret = dev_direct_xmit(skb, 0);
>  	if (ret)

You should release skb here too. So the better patch will be to write
something like that:

cleanup:
  stmmac_set_arp_offload(priv, priv->hw, false, 0x0);
  if (ret)
  	kfree_skb(skb);

Thanks

> -- 
> 2.9.5
> 

Re: [PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[Zhang Changzhong]

On 2022/12/7 17:12, Leon Romanovsky wrote:
> On Wed, Dec 07, 2022 at 04:31:59PM +0800, Zhang Changzhong wrote:
>> The skb allocated by stmmac_test_get_arp_skb() hasn't been released in
>> some error handling case, which will lead to a memory leak. Fix this up
>> by adding kfree_skb() to release skb.
>>
>> Compile tested only.
>>
>> Fixes: 5e3fb0a6e2b3 ("net: stmmac: selftests: Implement the ARP Offload test")
>> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
>> ---
>>  drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
>> index 49af7e7..687f43c 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
>> @@ -1654,12 +1654,16 @@ static int stmmac_test_arpoffload(struct stmmac_priv *priv)
>>  	}
>>  
>>  	ret = stmmac_set_arp_offload(priv, priv->hw, true, ip_addr);
>> -	if (ret)
>> +	if (ret) {
>> +		kfree_skb(skb);
>>  		goto cleanup;
>> +	}
>>  
>>  	ret = dev_set_promiscuity(priv->dev, 1);
>> -	if (ret)
>> +	if (ret) {
>> +		kfree_skb(skb);
>>  		goto cleanup;
>> +	}
>>  
>>  	ret = dev_direct_xmit(skb, 0);
>>  	if (ret)
> 
> You should release skb here too. So the better patch will be to write
> something like that:
> 

Hi Leon,

Thanks for your review, but I don't think we need release skb here,
because dev_direct_xmit() is responsible for freeing it.

Regards,
Changzhong

> cleanup:
>   stmmac_set_arp_offload(priv, priv->hw, false, 0x0);
>   if (ret)
>   	kfree_skb(skb);
>> Thanks
> 
>> -- 
>> 2.9.5
>>
> .
> 

Re: [PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[Leon Romanovsky]

On Wed, Dec 07, 2022 at 06:07:16PM +0800, Zhang Changzhong wrote:
> On 2022/12/7 17:12, Leon Romanovsky wrote:
> > On Wed, Dec 07, 2022 at 04:31:59PM +0800, Zhang Changzhong wrote:
> >> The skb allocated by stmmac_test_get_arp_skb() hasn't been released in
> >> some error handling case, which will lead to a memory leak. Fix this up
> >> by adding kfree_skb() to release skb.
> >>
> >> Compile tested only.
> >>
> >> Fixes: 5e3fb0a6e2b3 ("net: stmmac: selftests: Implement the ARP Offload test")
> >> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
> >> ---
> >>  drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c | 8 ++++++--
> >>  1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
> >> index 49af7e7..687f43c 100644
> >> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
> >> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
> >> @@ -1654,12 +1654,16 @@ static int stmmac_test_arpoffload(struct stmmac_priv *priv)
> >>  	}
> >>  
> >>  	ret = stmmac_set_arp_offload(priv, priv->hw, true, ip_addr);
> >> -	if (ret)
> >> +	if (ret) {
> >> +		kfree_skb(skb);
> >>  		goto cleanup;
> >> +	}
> >>  
> >>  	ret = dev_set_promiscuity(priv->dev, 1);
> >> -	if (ret)
> >> +	if (ret) {
> >> +		kfree_skb(skb);
> >>  		goto cleanup;
> >> +	}
> >>  
> >>  	ret = dev_direct_xmit(skb, 0);
> >>  	if (ret)
> > 
> > You should release skb here too. So the better patch will be to write
> > something like that:
> > 
> 
> Hi Leon,
> 
> Thanks for your review, but I don't think we need release skb here,
> because dev_direct_xmit() is responsible for freeing it.

Interesting, __dev_direct_xmit() releases skb too.
Thanks for the clarification.


> 
> Regards,
> Changzhong
> 
> > cleanup:
> >   stmmac_set_arp_offload(priv, priv->hw, false, 0x0);
> >   if (ret)
> >   	kfree_skb(skb);
> >> Thanks
> > 
> >> -- 
> >> 2.9.5
> >>
> > .
> > 

Re: [PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Wed, 7 Dec 2022 16:31:59 +0800 you wrote:
> The skb allocated by stmmac_test_get_arp_skb() hasn't been released in
> some error handling case, which will lead to a memory leak. Fix this up
> by adding kfree_skb() to release skb.
> 
> Compile tested only.
> 
> Fixes: 5e3fb0a6e2b3 ("net: stmmac: selftests: Implement the ARP Offload test")
> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
> 
> [...]

Here is the summary with links:
  - [net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()
    https://git.kernel.org/netdev/net/c/f150b63f3fa5

You are awesome, thank you!
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